CHPGST(1) LAPACK routine (version 3.2) CHPGST(1)NAME
CHPGST - reduces a complex Hermitian-definite generalized eigenproblem
to standard form, using packed storage
SYNOPSIS
SUBROUTINE CHPGST( ITYPE, UPLO, N, AP, BP, INFO )
CHARACTER UPLO
INTEGER INFO, ITYPE, N
COMPLEX AP( * ), BP( * )
PURPOSE
CHPGST reduces a complex Hermitian-definite generalized eigenproblem to
standard form, using packed storage. If ITYPE = 1, the problem is A*x
= lambda*B*x,
and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H) If
ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H*A*L. B must
have been previously factorized as U**H*U or L*L**H by CPPTRF.
ARGUMENTS
ITYPE (input) INTEGER
= 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
= 2 or 3: compute U*A*U**H or L**H*A*L.
UPLO (input) CHARACTER*1
= 'U': Upper triangle of A is stored and B is factored as
U**H*U; = 'L': Lower triangle of A is stored and B is factored
as L*L**H.
N (input) INTEGER
The order of the matrices A and B. N >= 0.
AP (input/output) COMPLEX array, dimension (N*(N+1)/2)
On entry, the upper or lower triangle of the Hermitian matrix
A, packed columnwise in a linear array. The j-th column of A
is stored in the array AP as follows: if UPLO = 'U', AP(i +
(j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i +
(j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. On exit, if INFO = 0,
the transformed matrix, stored in the same format as A.
BP (input) COMPLEX array, dimension (N*(N+1)/2)
The triangular factor from the Cholesky factorization of B,
stored in the same format as A, as returned by CPPTRF.
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
LAPACK routine (version 3.2) November 2008 CHPGST(1)